Dear All,
I have converted, and currently Singaporean without Pink IC.
Not sure if anyone shared the step next after receiving the IPA for Citizenship, so let me share my personal experience (while my memory still fresh):
0. You apply Citizenship from ICA and receive in-principle approval. DO NOT RENOUNCE your current citizenship
1. You are required to complete 3 tasks:
~ Online Journey: basically to enrich your knowledge about Singapore.
~ Singapore Experimental Tour (SET) which is half day Singapore Museum tour and a place of your choice (I chose Marina Barrage that time).
~ Community Sharing Session, this one is based on your GRC
Noted: no need to be in sequence, try to book Community Sharing Session first as normally its once a month only.
2. Once completed no 1 above, ICA will send you "Official" Approval Letter asking you to renounce your citizenship within an online appointment date (pls reschedule the appointment date if you cant make it in time).
3. I went to Indonesia Embassy with my Indonesian IC and Passport and was told those are not enough. I will need to:
a. go to Singapore Public Notary to do the Renounciation Letter you will need: ICA Approval letter, Indonesian Passport, IC (KTP), Family Card (Kartu Keluarga), Birth Cert (Akte Kelahiran), Citizenship Cert (SKBRI - If have, if not just declare on renounciation letter). As i dont know any Public Notary, Embassy gave me a reference (which im not sure if its appropriate to put it here) and i paid the Notary
$150 (inc GST) Can collect the letter on the same day.
b. bring the letter to Academy of Law to get the Public notary name and signature certified. submit before 12 noon and it will be ready the next day after 2pm
Paid $25 (before GST)
c. bring the whole stack renunciation documents from Academy of Law to Ministry of Foreign affair to be endorsed.
Paid $10 (inc GST), done on spot
Now, if you are lazy to handle yourself, the notary offer the service to do step b and c together for extra
$80 so total will be $230... as i want to experience the whole thing myself, i decide to do it myself (only then i can shares with you all lol

)
4. Bring ICA Approval Letter, Renunciation Letter, Birth Cert, IC (KTP), Passport, Citizenship Cert (SBKRI) if have, Family Cert (Kartu Keluarga), Marriage cert (if married), to Indonesia Embassy to renounce your citizenship. They require
Original and Copy of the documents. Paid $32 + $2 for Stamp (Materai). will take 5 working days. they took my passport and IC back and return only my birth cert with renunciation letter.
5. Based on the online appointment, bring the renunciation letter + approval letter + 4pc photo taken on 1st floor of ICA (have to 1st floor ICA building) + Blue IC to ICA, they will register your finger print, and use the photo for IC registration (paid $10) and citizenship cert (paid $70). They will punch a hole on your blue IC and then take oath... and you are Singaporean...
6. Passport application is optional. i done it thru online, save $10
7. Pink IC will be given on offical ceremony which they will send letter to you for the location and time.
I will add other info if i missed out something

hope it helps.
PS: other nationality steps to renounce their citizenship might be different. cheers.